Influence of Vitamin D on Vascular Function in Adolescents and Young Adults With Type 1 Diabetes

The Hospital for Sick Children33 enrolled

Overview

The purpose of this study is to study the role of low vitamin D levels on the health of blood vessels or vascular function in adolescents and young adults with type 1 diabetes.

Vitamin D deficiency is known to be common in patients with type 1 diabetes. Studies in adults have shown that vitamin D deficiency is associated with cardiovascular events such as stroke, myocardial infarction and peripheral arterial disease. However, the impact of this deficiency on vascular health in adolescents with diabetes has not been examined. Furthermore given that endothelial dysfunction is reversible, early detection of this process may have therapeutic and prognostic implications in this population.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Diabetes Mellitus, Type 1

Interventions

Vitamin DDIETARY_SUPPLEMENT

Dosing If the 25 OH Vitamin D level at Baseline/Screening is less than 20 nmol/L then the subject will receive 2000 IU daily. If the 25 OH Vitamin D level at Baseline/Screening is between 20 and 37.5 nmol/L then the subject will receive 1000 IU daily.

Eligibility

Sex: ALLMin age: 12 YearsMax age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Diagnosed with type 1 diabetes, according to Canadian Diabetes Association guidelines 2. Diagnosed with type 1 diabetes for at least 2 years 3. Between the ages of 12 and 18 years Exclusion Criteria: 1. Previous organ transplantation 2. Diagnosed with familial hypercholesterolemia 3. Active smoker 4. Receiving lipid lowering medications 5. Receiving anti hypertensive medication 6. Significant chronic medical illness, including granulomatous disease 7. History of hypertension 8. BMI \>95%tile 9. Known renal failure 10. HbA1c greater than 12% on two successive occasions 11. Known peripheral vascular disease 12. Known hypercalcemia

Locations (1)

The Hospital for Sick Children

Toronto, Ontario, Canada

Outcomes

Primary Outcomes

Comparison of Endothelial Function

We will compare endothelial function in adolescents with type 1 diabetes divided into 2 groups on the basis of vitamin D status (deficient and sufficient). Endothelial function will be assessed by peripheral arterial tonometry (PAT) which measures the elasticity of the arteries.

Time frame: Baseline

Change in Endothelial Function after Treatment with Vitamin D

We will measure the change in endothelial function from baseline in the children that were vitamin D deficient. This measurement will be done once the child has become vitamin D sufficient. Vitamin D status will be assessed at 3 months. If the levels remain deficient treatment would continue for another 3 months, with repeat testing at 6 months. Endothelial function will be assessed by peripheral arterial tonometry (PAT) which measures the elasticity of the arteries.

Time frame: Baseline, 3 or 6 months

Secondary Outcomes

Monitoring of Vitamin D Levels in Vitamin D deficient subjects

At a vist to take place at 2-3 months, the Vitamin D deficient sujects will undergo blood sampling for 25 hydroxyvitamin D levels to ensure appropriate treatment with D Drops to normalize 25 OH vitamin D levels greater than 50 nmol/L.

Time frame: 2-3 months

Monitoring of Calcium Creatine Ratio in Vitamin D deficient subjects

At a vist to take place at 2-3 months, the Vitamin D deficient sujects will have a urine assessment of spot calcium creatinine ratio to ensure that hypercalcemia (calcium/ creatinine ratio greater than 0.7) is not present.

Time frame: 2-3 months

Comparison of Systemic Blood Pressure

We will compare endothelial function in adolescents with type 1 diabetes divided into 2 groups on the basis of vitamin D status (deficient and sufficient).

Data from ClinicalTrials.gov

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